Automatic speed bump

ABSTRACT

The automatic speed bump is installed in a roadway to discourage motor vehicle travel at excessive speeds. The device includes a box-like structure set into the surface, the box having upper edges flush with the surface. Two doors are hinged to the box along their opposite edges. Concentric spring and shock absorber assemblies lift the centers of the doors to create a speed bump. A guide strut is installed between each spring and shock absorber assembly to maintain alignment of the apparatus. The springs and shock absorbers retract at a predetermined rate when a standard motor vehicle encounters the raised doors at a reasonable speed. The doors folding flush with the surface to allow the vehicle to travel over a flat surface. The shock absorbers cannot retract faster than their predetermined rate, resulting in the doors remaining raised when a vehicle travels over the device at higher than reasonable speed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to vehicular traffic control devices, and particularly to an automatic speed bump that is normally raised, but retracts upon vehicle contact at reasonable vehicle speeds.

2. Description of the Related Art

The control of motor vehicle speeds is a chronic problem in the field of traffic engineering and law enforcement. While posted speed limits are nearly universal on public roads, there is a tendency by some drivers to exceed those limits, and law enforcement cannot possibly maintain a watch at all times and places for such speeding traffic. Moreover, there are areas, such as shopping malls, school zones, and streets and intersections. with heavy pedestrian traffic in which the common relatively low posted speed limits are frequently violated.

Accordingly, some physical restriction to traffic speed is often installed in such areas where it is important that traffic speeds be kept low. These physical restrictions are generally in the form of the so-called “speed bump,” comprising a raised section extending laterally across substantially the entire width of the roadway. Such speed bumps generally need be only a very few inches high, and have a width (in the direction of vehicle travel) on the order of a foot. It will be seen that a vehicle traveling at a very slow speed will be subjected to a mild vertical displacement when encountering such a speed bump, but a vehicle traveling at an excessive speed will have much less time for the vehicle tires and suspension to absorb the impact and will, thus, be subjected to a significant jolt.

While such permanently installed speed bumps are quite simple and economical to install and maintain, they result in at least some disturbance to a smooth ride, even for motor vehicles transiting them at relatively slow speeds. Aside from the discomfort to vehicle occupants, the additional wear and tear on the vehicle suspension and structure takes its toll over an extended period of time, if such bumps must be negotiated frequently. This is a major factor in objections by local residents to the installation of speed bumps in many neighborhoods and localities, even though the alternative may be excessive speed by many vehicles traveling through the area and the resulting hazard to others in the area.

As a result, a number of positionable speed bumps have been developed in the past, with their intent being to allow the bump or obstruction to retract generally flush with the surface for motor vehicles traveling at a reasonable speed, but to remain raised for vehicles traveling at higher than desirable speeds. An example of such is found in European Patent Publication No. EP 664,361, published on Jul. 26, 1995. This reference describes (according to the drawings and English abstract) two interrelated devices pivotally installed below the surface of the roadway. Travel over the first results in its downward pivot until it encounters the second. Excessive speed results in excessive travel of the first element, which produces a lever action that raises the opposite end of the second element above the surface. This results in a significant impact to the speeding vehicle.

Thus, an automatic speed bump solving the aforementioned problems is desired.

SUMMARY OF THE INVENTION

The automatic speed bump is a laterally symmetrical apparatus, i.e., it has symmetry perpendicular to the orientation of traffic flow. First and second articulating doors that are hinged along their outboard edges and raised by a plurality of lift struts beneath. Each of the struts comprises a concentric coil spring and shock absorber assembly that lifts an upper crossmember upward to lift the adjacent free edges of the doors upward. A guide is installed between each of the lifting struts to maintain the proper alignment of all of the components. A central cover may be installed over the tops of the lift struts and guides, to prevent the entrance of debris and/or the entrance of animals or inadvertent stepping into the device by pedestrians. The entire apparatus includes a box-like structure that is set into the roadway. The hinged outboard edges of the doors are substantially flush or coplanar with the roadway surface.

The springs and shock absorbers of the lift struts are engineered to compress when a standard motor vehicle traveling at a reasonable speed encounters one of the raised doors or covers. The spring rate of all the springs is collectively sufficiently low that it allows them to compress, and the resistance of the shock absorbers is selected to allow them to compress over a sufficiently short time that it allows the doors to fold flush with the surface as the vehicle travels over them. A motor vehicle traveling at a higher rate of speed will not allow the shock absorbers to retract sufficiently rapidly so that the doors remain at least partially raised to produce a significant jolt to the vehicle as it passes over the device.

These and other features of the present invention will become readily apparent upon further review of the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an environmental, perspective view of an automatic speed bump according to the present invention, showing the speed bump in its raised position.

FIG. 2 is an environmental perspective view of the automatic speed bump of FIG. 1, showing the speed bump depressed due to the passage of a motor vehicle thereover.

FIG. 3 is a perspective view of the automatic speed bump of FIG. 1, shown partially broken away to illustrate various internal details thereof.

FIG. 4 is an end elevation view in section of the automatic speed bump according to the present invention, taken through one of the shock absorber and spring struts.

FIG. 5 is an end elevation view in section of the automatic speed bump according to the present invention, taken through one of the guide struts.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The automatic speed bump is configured to fold downward substantially flush with the roadway surface over a short but predetermined period of time when driven over by a motor vehicle. If the motor vehicle is traveling at a reasonable speed the retraction of the speed bump allows the vehicle to travel over the retracted speed bump with little or no vertical displacement of the vehicle. However, a motor vehicle traveling at a higher than permissible speed passes over the speed bump too rapidly to allow the bump to retract, resulting in a significant jolt to the vehicle and its occupants. The mechanism incorporates a number of shock absorbers and springs to accomplish the effect. The strength of the shock absorbers and springs are determined according to the number of units installed, the anticipated speed of traffic, and numerous other factors.

FIG. 1 of the drawings is an illustration of an installation of an exemplary automatic speed bump 10. The automatic speed bump 10 includes a box structure set into the roadway. The upper edges of the box are substantially flush with the roadway surface. FIG. 3 illustrates substantially the complete speed bump 10 structure, and is discussed further below. Two elongate doors 12 a and 12 b are attached to the opposite upper edges of the box structure by hinges. The underlying mechanism raises the central portions of the two doors when the lifting mechanism is in an uncompressed state. An elongate central cover 14 extends between the two doors 12 a, 12 b to protect the mechanism and to tie together the various lift struts and guides of the lifting mechanism.

FIG. 2 of the drawings provides an illustration of the operation of the automatic speed bump 10 when a motor vehicle V travels over the speed bump 10 at a reasonable speed. The wheels of any motor vehicle will require a finite amount of time to travel across the automatic speed bump 10. That time varies inversely according to the speed of the vehicle. The mechanism of the automatic speed bump 10 is configured to require a short but finite amount of time to retract upon receiving the force imparted by the tires of a motor vehicle. If the motor vehicle is traveling at a moderate or reasonable speed, the mechanism of the automatic speed bump 10 has sufficient time to retract and allow the doors 12 a and 12 b to fold substantially flush with the adjacent roadway surface, substantially as shown in FIG. 2 of the drawings. Thus, a motor vehicle V and its occupants traveling at a moderate speed are not subjected to any significant jarring or jolting as they travel over the speed bump 10.

FIG. 3 of the drawings is a perspective view of the automatic speed bump 10, in which the central portions of the two doors 12 a, 12 b and central cover 14 are broken away to reveal a portion of the internal mechanism. FIGS. 4 and 5 are elevation views in section through various components of the internal mechanism, some of the box structure being shown best in FIGS. 4 and 5. The automatic speed bump 10 comprises an elongate, rigid box structure 16 that is set into the surface of the roadway for operation. The box 16 includes a floor 18, mutually opposed first and second sides 20 a and 20 b, mutually opposed first and second ends 22 a and 22 b, and an open top 24 (shown most clearly in FIGS. 4 and 5). Each of the two sides 20 a and 20 b has an upper edge, respectively 26 a and 26 b, to which the respective doors 12 a, 12 b are attached by hinges 28, as shown in FIGS. 4 and 5. The opposite free edges 30 a and 30 b of the two doors 12 a and 12 b face one another across the central cover 14, as shown in each of the drawings, and particularly in FIGS. 4 and 5. Each of the two doors 12 a, 12 b has a lower surface, respectively 32 a and 32 b. The lifting or controlling mechanisms are illustrated in detail in FIGS. 4 and 5, bearing against the door lower surfaces 32 a and 32 b.

The two doors 12 a, 12 b, or more precisely their mutually facing free edges 30 a and 30 b, are held in a partially open or raised configuration by a plurality of spring and shock absorber assemblies 34, one of which is illustrated in detail in FIG. 4. Each of the spring and shock absorber assemblies 34 comprises a base tube 36 having an open upper end 38 and an upper tube 40 telescoped into the base tube 36. The two tubes 36 and 40 may have square, circular, or other cross-sectional shapes. A shock absorber 42 is installed within the base tube 36. The shock absorber has one end connected to the floor 18 of the box structure 16, and its opposite end is connected to the lower portion of the upper tube 40. The shock absorber 42 may be of any conventional operating principle, i.e., hydraulic or pneumatic. A coil spring 44 is installed about the shock absorber 42. The spring 44 and shock absorber 42 are disposed concentrically within the base tube 36.

The upper end of each of the spring and shock absorber assemblies, i.e., the upper end 46 of the upper tube 40, has a crossmember 48 extending thereacross. The central cover 14 is affixed to and extends across all of the crossmembers 48 of the plurality of spring and shock absorber assemblies 34 within the box 16. Each of the crossmembers 48 has mutually opposed first and second ends 50 a and 50 b, each end 50 a, 50 b having a roller 52 a, 52 b installed thereon. The rollers 52 a and 52 b bear against the respective lower surfaces 32 a and 32 b of the two doors 12 a and 12 b, urging the doors upward to a partially open state when the spring 44 is generally uncompressed, as shown in FIGS. 3 and 4 of the drawings. The travel of the doors 12 a and 12 b may be limited according to the maximum extension of the shock absorber 42, or by some other stop or limit mechanism or device.

An additional plurality of alignment guides 54 is also installed within the box 16. The alignment guides 54 are installed in an alternating array between each of the spring and shock absorber assemblies 34. FIG. 5 provides a detailed elevation view in section of an exemplary alignment guide 54. Each of the alignment guides 54 comprises a base tube 56 having an open upper end 58, and mutually opposed first and second guide rollers 60 a and 60 b installed at the upper end 58 of the base tube 56. A closely fitting alignment bar 62 telescopes in and out of the base tube 56. Friction is minimized between the alignment bar 62 and the interior of the base tube 56 by the two guide rollers 60 a and 60 b. The upper end 64 of the alignment bar 62 has a crossmember 66 affixed thereacross, in a manner similar to the crossmembers 48 of each of the spring and shock absorber assemblies 34. The alignment bar crossmember 66 has mutually opposed first and second ends 68 a and 68 b and a roller 70 a, 70 b installed on the two crossmember ends 68 a and 68 b. The alignment bar crossmember rollers 70 a and 70 b bear against the respective lower surfaces 32 a and 32 b of the two doors 12 a and 12 b, in a manner similar to the spring and shock absorber crossmember rollers 52 a and 52 b.

Although there is no device within the base tube 56 urging the alignment bar 62 upward, the alignment guide crossmember 66 of each of the guides 54 is affixed to the central cover 14. Since the central cover 14 is lifted by the crossmembers 48 of the spring and shock absorber assemblies 34, and since the central cover 14 is affixed to the alignment guide crossmembers 66 to connect them to the spring and shock absorber crossmembers 48, it will be seen that the guide bars 62 of the alignment guides 54 will be telescoped in and out of their respective base tubes 56 to maintain the alignment of the upper tubes 40 within the base tubes 36 when the spring and shock absorber assemblies 34 operate according to traffic passing over the doors 12 a and 12 b.

It will also be noted that the box 16, its two doors 12 a and 12 b, the central cover 14 therebetween, the spring and shock absorber assemblies 34, and the alignment guide assemblies 54 comprise a laterally symmetrical structure about a vertical plane P disposed along the elongate centerline of the structure, parallel to the two sides 20 a and 20 b of the box 16. In this manner, the automatic speed bump 10 may be installed without regard for the direction of traffic flow. While most traffic will flow in a single direction in any given lane of traffic, there are occasions when traffic flow is reversed, e.g., to facilitate inbound or outbound flow during rush hour, etc. Thus, the automatic speed bump 10 may be installed in such situations without regard for the direction of traffic flow, and will serve equally well to encourage reasonable traffic speeds, regardless of the direction of traffic flow.

It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims. 

1. An automatic speed bump, comprising: an elongate, rigid box having a floor, mutually opposed first and second sides, mutually opposed first and second ends, and an open top, each of the sides of the box having an upper edge; a first door pivotally attached to the upper edge of the first side, the first door having a free edge and a lower surface; a second door pivotally attached to the upper edge of the second side, the second door having a free edge and a lower surface, the free edges of each of the doors facing one another; a plurality of spring and shock absorber assemblies extending upward from the floor of the box, each of the spring and shock absorber assemblies lifting the free edges of the first door and the second door to a partially open state above the box when the spring and shock absorber assemblies are in an uncompressed state; a crossmember having mutually opposed first and second ends; an elongate cover seated on the crossmember; and first and second rollers respectively disposed at the first and second ends of the crossmember, wherein said first and second rollers bear against the respective lower surfaces of the first and second doors adjacent their free edges thereof when the spring and shock absorber assemblies are in an uncompressed state such that said first and second rollers support the respective lower surfaces of said first and second doors; wherein the box, the doors, and the spring and shock absorber assemblies collectively form a laterally symmetrical structure about a vertical plane parallel to the first and second sides of the box.
 2. The automatic speed bump according to claim 1, further comprising a plurality of alignment guides extending upward from the floor of the box, the alignment guides and the spring and shock absorber assemblies being disposed in an alternating array, wherein the elongate cover is affixed to each of the spring and shock absorber assemblies and to each of the alignment guides, the cover connecting the spring and shock absorber assemblies and the alignment guides to one another, the cover maintaining lateral alignment of the alignment guides and the spring and shock absorber assemblies.
 3. The automatic speed bump according to claim 2, wherein each of the alignment guides further comprises: a base tube having an open upper end; mutually opposed first and second rollers disposed at the upper end of the base tube; an alignment bar telescopically disposed in the base tube, the alignment bar having an upper end, wherein the crossmember is disposed across the upper end of the alignment bar.
 4. The automatic speed bump according to claim 1, wherein each of the spring and shock absorber assemblies has an upper end, the crossmember being disposed across the upper end of each of the spring and shock absorber assemblies.
 5. The automatic speed bump according to claim 4, wherein each of the spring and shock absorber assemblies further comprises: a base tube having an open upper end; an upper tube telescopically disposed in the base tube, the upper tube having an upper end, the crossmember being disposed across the upper end; and a coil spring and a shock absorber disposed concentrically within the base tube and the upper tube.
 6. The automatic speed bump according to claim 1, wherein each of the shock absorbers of the shock absorber and spring assemblies comprises a hydraulic shock absorber.
 7. The automatic speed bump according to claim 1, wherein each of the shock absorbers of the shock absorber and spring assemblies comprises a pneumatic shock absorber. 8-20. (canceled) 